Tunable optical limiting of gold nanorod thin films

Optical limiting frequency and bandwidth of nanocomposite films containing gold nanorods embedded in a dielectric matrix were investigated by using Maxwell-Garnett (MG) effective medium model and quasi-static theory. Because of the morphological anisotropy of the gold nanorods, there are two bands of optical limiting taking place in the visible and near infrared region. A large variation of the optical limiting frequency from 530 to 820 nm was obtained by increasing the aspect ratio of gold nanorods from 1.0 to 5.0. Furthermore, the bandwidth of optical limiting can also been tuned from 50 to 190 nm by increasing the gold volume fraction from 10% to 30%.